The following abbreviations are herewith defined, at least some of which are referred to within the following description of the state-of-the-art and the present invention.
DBA Dynamic Bandwidth Allocation
DM Doze Mode
DS Downstream
DSM Dynamic Sleep Mode
EA Ethernet Aggregation
GPON Gigabit PON
FSM Fixed cyclic Sleep Mode
FWI Forced Wakeup Indication
LPTM Low-Power Transmit Mode
LSI Local Sleep Indication
LWI Local Wakeup Indication
OLT Optical Line Terminal
ONU Optical Network Unit
PBW Pre-allocated Band Width
PON Passive Optical Network
PtP Point to Point
SA Sleep Allow
SM Sleep Mode
SR Status Report
STM Sleep-Transmit Mode
TDM Time Division Multiplexing
UNI User Network Interface
QoS Quality of Service
US Upstream
XG-PON 10-Gigabit PON
A computer network, generally speaking, includes a number of computing devices linked together for any of a number of reasons including the sharing of data and computing resources and the control of remote devices. In addition, a major function of many if not all computer networks is communication between two or more entities within or through the network, and for this reason networks performing this function will generally be referred to as communication networks. Communication networks may be implemented in a wide variety of environments, some of which are described herein.
Likewise, a wide variety of computing devices, sometimes referred to as nodes, some common and some more specialized, may be used in communication networks. The nodes of a communication network frequently though not universally contain a transmitter for forming and sending signals representing data over a communication channel, and a receiver for receiving and processing signals sent from another node. The communication channel may take several forms, including a wire or cable, an optical fiber, or radio or microwave frequency. The channel between any two devices may or may not be a direct connection; a number of intervening components or transmission media may be involved.
A shared communication channel is one used for transmission by multiple devices, where some agreed protocol or method of operation must be in place to avoid or otherwise deal with simultaneous transmissions. Note that in this context, concurrent use of a single medium may be facilitated by the use, for example, of separate radio frequencies or light wavelengths so the transmissions do not unduly interfere with each other. But in that case, each frequency or wavelength forms a separate channel (which may or may not be shared with other devices).
As with any network, efficient operation of communication networks is always a goal and there have been many improvements made in this endeavor. One improvement that has been made is the introduction of different operating states and modes. In this context, “state” describes the condition of certain components of a network node, for example whether the transmitter and receiver are turned on for use or off to save power. An operating “mode” usually anticipates cycling or a combination of transitions between two or more different states while the node is in that mode. Both the mode duration and the state transitions while in the mode may be based on a set schedule period or on the occurrence of one or more events.
When a component is in an “awake” state, for example, it is usually considered fully operational. In this state, however, it is consuming whatever amount of power this constant level of operation requires. To reduce the power consumption, a component may, for example, be put in a “sleep” state when it is not needed. In the sleep state the component usually does not send or receive communications, but turns off its transmitter and receiver to operate with minimal-power usage. A component in a sleep state may “awaken” at the appropriate time or when prompted in some other manner. A low-power mode may involve periodic cycling between the awake and sleep states.
As should be apparent, care must be used when executing operating-mode changes so as not to unduly disrupt desirable communications while still reaping the benefits of power-saving modes of operation. Redundant equipment, for example, may be put in sleep mode during periods when little communication activity is underway. An increase in traffic may in this case cause sleeping components to awaken, or they may do so according to some schedule. In some cases, components may be put in a sleep state where the any arising transmissions can be buffered to be sent after a return to the awake state. In this case, there is a trade-off between power savings and some delay in transmission.
These and other problems are addressed by embodiments of the present invention.
Note that the techniques or schemes described herein as existing, possible, or desirable are presented as background for the present invention, but no admission is made thereby that these techniques and schemes or the need for them were heretofore commercialized or known to others besides the inventors.